Integrating palliative care and oncology – a realist synthesis to explain what works, for whom, and in what circumstances. 

Introduction: Palliative care aims to improve quality of life for people living with a life-limiting illness. There are approximately 2.5 million people with cancer in the UK, and this may reach 4 million by the year 2030. An integrated approach to palliative care and cancer care is recommended to achieve continuity of care and address unmet needs. However, this is not yet common practice - symptom burden, futile treatment, and fragmented care continue to be significant issues that impede quality of life for patients and their families. Existing evidence demonstrates the benefits of integrated palliative care in oncology, for symptom burden, quality of life, and health service resource use. However, we do not know which interventions produce the best outcomes for patients and families, when best to initiate palliative care (for whom, or at what stage in the disease trajectory), or the optimal delivery method in terms of healthcare settings, the necessary infrastructure, and required staff competencies. Aims: We aim to explain how integrated palliative care in oncology works, for whom, and in what contexts; and to use this understanding to develop guidance to optimise integration. Methods: Realist synthesis is a theory-driven approach to a literature review, designed to understand complex interventions or phenomena by illuminating the interactions between context and mechanisms in leading to outcomes. The realist synthesis involves five iterative stages: 1) locating existing theories; 2) searching for evidence; 3) article selection; 4) extracting and organising data; 5) synthesising evidence and drawing conclusions. This synthesis is supported by an international stakeholder group, comprising healthcare professionals, NHS management, community groups, and public contributors. Close collaboration with this group ensures our findings are communicated in ways that meet the needs of key audiences, and that implications are relevant to current practice. Results: Emerging findings indicate that the integration of palliative care is more likely when: -Professionals across multiple disciplines work together effectively, -There is continuity of care across different care settings, -There are positive perceptions of palliative care, -There is education for healthcare professionals and for patients and caregivers. Conclusion: Through the synthesis of a range of evidence, this project contributes a detailed understanding of how integrated palliative care and cancer care can be achieved. Ongoing refinement of findings with our stakeholder group allows for implications to be co-produced, and facilitates our dissemination strategies. Therefore, the project helps to realise the benefits of integrated care for adults with cancer, i.e., improved symptom management, quality of life, and appropriate use of health service resources.